Double flanged bushings and installation methods

ABSTRACT

A dual bushing installation kit includes a first metal bushing and a second metal bushing. The first metal bushing can include a first body having first and second ends. The first and second ends are connected by a first outer surface having a first outer circumference and a first inner surface having a first inner circumference. The second metal bushing is defined by a second body having first and second ends. The first and second ends are connected by a second outer surface having a second outer circumference and a second inner surface having a second inner circumference. The second outer circumference is dimensioned to be substantially conforming with the first inner circumference such that the second bushing is closely receivable by a first opening of the first bushing. Both the second outer circumference and the first inner circumference can be expanded in an outwardly radial direction.

TECHNICAL FIELD

The present invention relates to the provision and installation oftubular bushings in openings in work members. More particularly, itrelates to the provision of bushings having flanges at both ends and tomethods of radially expanding tubular portions of the bushings to createa tight interference fit between them and the openings in the workmember.

BACKGROUND OF THE INVENTION

It is known to secure a bushing within an opening in a structural wallby positioning the bushing-within the opening, holding it in place, andthen forcing an expansion mandrel through the bushing to radially expandthe bushing into an interference fit with the opening.

U.S. Pat. No. 4,809,420, granted Mar. 7, 1989, to Michael A. Landy, ToddL. Thompson and Larry I. Wiemann, and U.S. Pat. No. 5,433,100, grantedJul. 18, 1995, to Eric T. Easterbrook, Todd L. Thompson and Mark R.Weiss, both disclose the use of a mandrel alone for installing bushingsin openings in a work member.

U.S. Pat. No. 4,557,033, granted Dec. 10, 1985, to Robert L. Champoux,discloses using a mandrel alone for cold expanding an opening in a workmember for the purpose of introducing fatigue life enhancing compressiveresidual stresses in the work member immediately around the opening inthe work member.

U.S. Pat. No. 5,103,548, granted Apr. 14, 1992, to Leonard F. Reid andRoger T. Dolstad discloses the use of a mandrel and a split sleevetogether for installing a tubular bushing in an opening in a work memberand at the same time introducing fatigue life enhancing compressiveresidual stresses in the work member.

The contents of U.S. Pat. Nos. 4,557,033; 4,809,420 and 5,103,548 arehereby incorporated herein by this specific reference.

U.S. Pat. No. 3,835,688, granted Sep. 17, 1974, to John O. King, Jr. andU.S. Pat. No. 3,949,535, granted Apr. 13, 1976, also to John O. King,Jr. each discloses a method of both installing a seamless tubular memberin openings in two members to be joined and expanding the materialimmediately surrounding the openings for the purposes of fatigue lifeenhancement. The seamless tubular members disclosed by these patentshave a flange at one end that contacts the side of one of the membersfrom which the tubular member is inserted. U.S. Pat. No. 3,949,535discloses providing a flare on the end of the sleeve opposite the flangeto assist in retaining the sleeve in the opening in the workpiece. Thisflare is formed by the movement of the mandrel through the sleeve and itrequires a particular end construction of the sleeve.

Thus, it is known to provide a bushing with a radial flange at one ofits ends. There is a need for providing a bushing that has a radialflange at each of its ends. For example, when bushings are used in a lugor clevis, there is a potential of face-to-face contact between thejoined parts. Flanges on both ends of the bushing would protect theface-to-fact contact of the parent material in which the bushing hasbeen installed. The flanges could be used to react a load applied to thelug or clevis along a line parallel to the bore of the lug or clevis.For example, in a landing gear lug on an aircraft, the lug might see aload transmitted to the pin through the lug perpendicular to the axis ofthe bore, due to the weight of the aircraft. However, it could also seean axial load due to the fore and aft loading of the lug. A secondflange on a bushing could also be used to provide a surface on which anut and washer may seat when a threaded pin is used to retain the pin inthe joint. The principal object of the present invention is to providetubular bushings having flanges at both of their ends. Another object isto provide methods of making and installing tubular bushings that haveflanges at both ends.

U.S. Pat. Nos. 3,835,688 and 3,949;535, and the other above-identifiedpatents should be carefully considered for the purpose of putting thepresent invention into proper prospective relative to the prior art.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, a workpiece is provided thatincludes first and second sides and a cylindrical opening extendingthrough it between the two sides. A bushing is provided that includes atubular center portion that is placed within the cylindrical opening. Afirst radial flange is connected to the tubular center portion of thebushing on the first side of the work member. This flange extendsradially outwardly from the tubular center portion of the bushing, incontact with the first side of the work member. A second radial flangeis connected to the tubular center portion of the bushing on the secondside of the work member. This second radial bushing extends radiallyoutwardly from the tubular center portion of the bushing, in contactwith the second side of the work member. The tubular center portion ofthe bushing is radially expanded in the cylindrical opening to such anextend that it makes a tight interference fit within the opening andconnects the bushing to the work member.

According to one aspect of the invention, the tubular center portion ofthe bushing is a single continuous tubular member that is connected atone end to the first flange and which includes a second end portion thatextends axially outwardly beyond the second side of the work member. Thesecond flange is a radial member having a center opening in which theprojecting end portion of the tubular member is received. The tubularmember is radially expanded in the center opening of the second flangeto such an extent that it makes a tight interference fit with theopening in the second flange and connects the second flange to thetubular member.

According to another aspect of the invention, the bushing is composed ofa first bushing part that includes the first flange and a first tubularmember that is connected to the first flange, and a second bushing partthat includes the second flange and a second tubular member that isconnected to the second flange. The two tubular members together form atleast a part of the central portion of the bushing. The first tubularmember may extend substantially completely through the opening and thesecond tubular member may be positioned in the first tubular member andextends substantially completely through it. The two tubular members areconcentric. The radial expansion connects the first tubular member tothe sidewall of the opening and connects the second tubular member tothe first tubular member.

According to another aspect of the invention, the first tubular memberextends axially from a first flange into and partially through thecylindrical opening in the work member. The second tubular memberextends from the second flange into and partially through the opening inthe work member, coaxial with the first tubular member. The outsidediameters of the tubular members may be close in size to the insidediameter of the opening, so that when radially expanded, the two tubularmembers make a tight interference fit with the opening in the workmember. Or, the first and second tubular members may be surrounded by athird tubular member, in which case the radial expansion connects thefirst tubular member to the sidewall of the opening in the work memberand connects the second and third tubular members of the bushing partsto the first tubular member. That is, the third tubular member makes atight interference fit with the cylindrical opening in the work memberand the second and third tubular members make tight interference fitswith the first tubular member.

The present invention also includes methods for installing doubleflanged bushings in openings in work members. According to a firstmethod aspect of the invention, a work member is provided that has afirst side and an opposite second side. A cylindrical through opening isprovided in the work member, extending from the first side to the secondside. A first bushing part is provided that has a tubular section and aradial flange section at one end of the tubular section. The tubularsection has an outside diameter substantially corresponding to thediameter of the through opening in the work member. The tubular sectionof the first bushing part is inserted into and through the opening inthe work member, from the first side of the work member. The firstbushing part is moved axially to place its flanged section against thefirst side of the work member. The tubular section of the first bushingpart is of such a length that when the flange section is against thefirst side of the work member, the tubular section has an end portionopposite the flanged section that projects axially outwardly of theopening, beyond the second side of the work member. A second bushingpart includes a center opening that is sized to receive the projectingend portion of the tubular section of the first bushing part. The secondbusing part extends radially outwardly from this center opening. Thesecond bushing part is positioned on the projecting end portion of thetubular section of the first bushing part and is moved substantiallyagainst the second side of the work member. Then, the tubular section ofthe first bushing member is radially and circumferentially expanded anamount sufficient to provide a tight interference fit between it and thethrough opening in the work member and between its projecting endportion and the opening in the second bushing part. This connects thefirst bushing part to the work member and connects the second bushingpart to the projecting end portion of the tubular section of the firstbushing part, such that the second bushing part functions as a secondflange at the end of the first bushing part that is opposite the flangesection of the first bushing part.

The tubular section of the bushing part may be radially expanded anamount sufficient to also introduce fatigue life enhancing compressiveresidual stresses in the work member immediately around the opening inthe work member.

The cold expansion of the tubular section, both for connecting it to thework member and the second bushing part, and for introducing fatiguelife enhancing compressive residual stresses in the work member, may beaccomplished by moving a tapered mandrel axially through the firstbushing part, and providing the mandrel with a large diameter endportion that is sized such that when it moves through the tubularsection of the first bushing part it will radially expand the tubularsection of the first bushing part to the extent needed.

According to another aspect of the invention, a first bushing part isprovided that has a tubular section and a radial flange section at oneend of its tubular section. The tubular section of the first bushingpart is provided with an outside diameter substantially corresponding tothe diameter of the opening in the work member. The second bushing partis provided that has a tubular section and a radial flange section atone end of its tubular section. The tubular section of the secondbushing part is provided with an outside diameter substantiallycorresponding to the inside diameter of the tubular section of the firstbushing part. The tubular section of the first bushing part is movedinto and through the opening in the work member, from the first side ofthe work member. It is moved axially until its flange section issubstantially against the first side of the work member. Then, thetubular section of the second bushing part is inserted into the tubularsection of the first bushing part, from the second side of the workmember. The second bushing part is then moved axially to place itsflange section substantially against the second side of the work member.The tubular sections of the first and second bushing parts are radiallyand circumferentially expanded together, an amount sufficient to providea tight interference fit of the tubular section of the second bushingpart in the tubular section of the first bushing part, and a tightinterference fit of the tubular section of the first bushing part in theopening in the work member. They also may be radially andcircumferentially expanded an amount sufficient to also introducefatigue life enhancing compressive residual stresses in the work memberimmediately around the opening in the work member.

According to a further aspect of the invention, a first bushing part isprovided that has a tubular section and a radial flange at one end ofthe tubular section. The tubular section has an outside diametersubstantially corresponding to the diameter of the opening in the workmember and a length that is only a portion of the length of the openingin the work member. A second bushing part is provided that has a tubularsection and a radial flange at one end of the tubular section. Thistubular section also has an outside diameter substantially correspondingto the diameter of the opening in the work member and a length that isless than the length of the opening in the work member. The tubularsection of the first bushing part is inserted into the opening in thework member, from the first side of the work member, and is movedaxially to place the flange section of the first bushing part againstthe first side of the work member. The tubular section of the secondbushing part is inserted into the opening in the work member, from thesecond side of the work member, and is moved axially until the flangesection of the second bushing part is against the second side of thework member. Then, the two tubular sections are radially andcircumferentially expanded an amount sufficient to provide a tightinterference fit between them and the opening in the work member, forconnecting the first and second bushing parts to the work member. Thecold expansion may also be sufficient to introduce fatigue lifeenhancing compressive residual stresses in the work member immediatelyaround a through opening in the work member.

According to yet another aspect of the invention, a tubular firstbushing part is provided that has an outside diameter substantiallycorresponding to the diameter of the opening in the work member and alength substantially corresponding to the length of the opening in thework member. A second bushing part is provided that has a tubularsection and a radial flange section at one end of the tubular section.The tubular section of the second bushing part has an outside diametersubstantially corresponding to the inside diameter of the first bushingpart and a length that is a portion of the length of the first bushingpart. A third bushing part is provided. It has a tubular section and aradial flange section at one end of the tubular section. The tubularsection of the third bushing part also has an outside diametersubstantially conforming to the inside diameter of the first bushingpart and a length that is a portion of the length of the first bushingpart. The first bushing part is inserted into the opening in the workmember. Then, the tubular section of the second bushing part is insertedinto the first bushing part, from the first side of the work member. Thesecond bushing part is moved axially until its flange section is againstthe first side of the work member. Next, the tubular section of thethird bushing part is inserted into the first bushing part, from thesecond side of the work member. The third bushing part is moved axiallyuntil its flange section is against the second side of the work member.Then, the first bushing part and the tubular sections of the second andthird bushing parts are radially expanded together an amount sufficientto provide a tight interference fit between the first bushing part andthe opening in the work member and between the tubular sections of thesecond and third bushing parts and the first bushing part. The bushingparts are expanded circumferentially an amount sufficient to connect thesecond and third bushing parts to the first bushing part and connect thefirst bushing part to the work member. They also may be radiallyexpanded an amount sufficient to introduce fatigue life enhancingcompressive residual stresses in the work member substantiallysurrounding the through opening in the work member.

Other objects, advantages and features of the invention will becomeapparent from the description of the best mode set forth below, from thedrawings, from the claims and from the principles that are embodied inthe specific structures that are illustrated and described.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

Like reference numerals are used to designate like parts throughout theseveral views of the drawing, and:

FIG. 1 is an exploded pictorial view of prior art tooling for installinga tubular bushing in an opening in a work member;

FIG. 2 is a pictorial view in longitudinal section of two flangedbushing that forms a part of the present invention;

FIG. 3 is a view like FIG. 2, showing a second two flanged bushing thatis a part of the present invention;

FIG. 4 is a view like FIGS. 2 and 3, showing a third two flanged bushingthat is a part of the invention;

FIG. 5 is a view like FIGS. 2–4 showing a fourth two flanged bushingthat is a part of the present invention;

FIG. 6 is a fragmentary sectional view showing the tooling of FIG. 1being used to install a bushing of the type shown by FIG. 2, such viewshowing a first bushing part having a tubular portion that is in anopening in the wall and a radial flange at one end that is against afirst side of the wall, and a second bushing part in the form of anannular member surrounding an end part of the tubular portion of thefirst bushing part that projects outwardly of the opening, beyond thesecond side of the work member, and such view showing a mandrel in anextended position within the tubular portion of the first bushing part;

FIG. 7 is a view like FIG. 6 but showing the mandrel being retracted andshowing an enlarged end portion of the mandrel radially expanding thetubular portion of the first bushing part as it moves through it;

FIG. 8 is a view like FIGS. 6 and 7, showing the mandrel in a retractedposition and the nose piece of the puller tool being moved away from theinstalled bushing;

FIG. 9 is a view like FIG. 7, but showing the tooling being used toinstall a bushing of the type shown by FIG. 3;

FIG. 10 is a view like FIGS. 7 and 9, but showing the tooling being usedto install a bushing of the type shown by FIG. 4;

FIG. 11 is a view like FIGS. 7, 9 and 10 but showing the tooling beingused to install a bushing of the type shown by FIG. 5;

FIG. 12 is a longitudinal sectional view showing a bushing of the typeshown in FIG. 2 installed in an opening in a work member;

FIG. 13 is a view like FIG. 12, but showing a bushing of the type shownby FIG. 3;

FIG. 14 is a view like FIGS. 12 and 13, but showing a bushing of a typeshown by FIG. 4;

FIG. 15 is a view like FIGS. 12–14, but showing a bushing of the typeshown by FIG. 5;

FIG. 16 is an enlarged scale fragmentary view of an upper centralportion of FIG. 15, such view showing that the bushing end parts mayhave concentric lapping portions where they meet; and

FIG. 17 is a view like FIG. 16, but of the upper central region of FIG.14, such view showing that the end parts of the bushing can haveconcentric lapping portions where they meet, the same as shown in FIG.16.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows prior art tooling for installing a prior art bushing 10.The tooling includes a puller 12 that includes a nose piece 14 having aforward end surface 16 and a mandrel receiving opening 18. In thissystem, the mandrel M includes a small diameter inner end portion 20that extends into the puller 12 via the opening 18. It further includesa bushing receiving central portion 22 and an enlarged end portion 24.In this system, it is necessary to slide the bushing 10 onto the mandrelfrom the smaller end of the mandrel M and then insert the mandrel intothe puller and connect it to a piston that is inside the puller 12. Thisinstallation of the mandrel M is shown by the aforementioned U.S. Pat.Nos. 4,809,420 and 5,433,100. Reference is made to U.S. Pat. No.5,433,100 for a more complete description and disclosure of the mandreland puller assembly.

FIGS. 2, 6–8 and 12 disclose a first embodiment of the double flangedbushings of the present invention. This bushing 25 is composed of afirst bushing part 26 and a second bushing part 28. Bushing part 26comprises a tubular section 30 and a radial flange section 32. Flangesection 32 is connected to one end of the tubular section 30. Tubularsection 26 extends axially and radial flange section 32 extendsradially. Bushing part 28 is a radial member 34 that includes a centeropening 36. Preferably, but not necessarily, the radial length of member34 substantially equals the radial length of flange section 32 measuredfrom the outside diameter of the tubular section 30.

A through opening 38 is provided in a work member 40 to receive thebushing 25. An initial opening 38 is formed by use of a drill. Thedrilled opening is then reamed to provide a desired starting diameter.After reaming, the starting diameter is verified by use of ahole-diameter gauge. If the opening 38 is oversized, it must be reworkedto provide it with a proper slightly larger diameter. An appropriateprimer may be applied to the opening 38.

FIGS. 6–8 show the bushing 28 in the process of being installed into theopening 38 in a work member 40, shown in the form of a structural wall40. The tubular section 30 of bushing part 26 has an outside diametersubstantially corresponding to the diameter of opening 38. Tubularsection 30 has a length that is slightly longer than the length of theopening 38, so as to provide it with an end portion 42 that projectsaxially outwardly from the second wall 44 of the member 40 when theflange 32 is against the first wall 46 of the member 40. The opening 36in member 34 has a diameter substantially corresponding to the outsidediameter of end part tubular section 30. End portion 42 has a lengthsubstantially corresponding to the thickness of the member 34.

As shown by FIG. 6, the tubular section 30 of member 26 is inserted intothe opening 38, from the first side of the member 40. It is movedaxially through the opening 38 until the radial flange 32 contactssidewall 48. When this happens, the end portion 42 of tubular section 30projects axially outwardly of the opening 30, beyond the second surface44. It may be desirable to apply a sealant to the inwardly side of theflange 32. Next, the second bushing part 28 is installed on this endportion 42. Bushing part 28 is moved towards the end portion 42 untilthe end portion 42 is inside the opening 36. It might be desirable toapply a sealant to the inward surface of bushing part 28. Then, themandrel M is inserted through the tubular section 30, from the firstside of the member 40. Its inner end portion 20 is connected to a pistoninside of the puller 12, such as is disclosed in U.S. Pat. No.5,433,100, with reference to FIGS. 20 and 21 of that patent. Followingconnection of the mandrel M to the puller 12, mandrel section 22 isinside the tubular section 30 and the enlarged end portion 24 of themandrel M is spaced from the first side 46 of member 40. The surface 16on nose piece 14 is positioned against member 34 such that member 34 isclamped between surface 16 and surface 44. Then, the puller 12 isoperated to retract the mandrel M and pull it through the tubularsection 30.

FIG. 7 shows the mandrel M in the process of being retracted and showsits enlarged end portion 24 in the process of stretching and enlargingtubular section 30 both radially and circumferentially as it movesthrough tubular section 30. During this movement, the drag of themandrel head 24 on the tubular section 30 pulls the flange 32 of bushingpart 26 tight against surface 26. A reaction to the pulling force movesthe nose piece 14 forwardly to place its forward surface 16 into tightcontact with the radial member 34. Thus, movement of the mandrel M pullsflange 32 into tight contact with surface 46 and pushes the member 34into tight contact with surface 44. At the same time, the tubularsection 30 is expanded to make a tight interference fit with thesidewall of opening 38. As the enlarged portion 22 of the mandrel Mmoves through the end portion 42 of tubular section 38, it radially andcircumferentially expands the end portion 42, causing a tightinterference fit between it and the sidewall of opening 36 in member 34.

FIG. 8 shows the mandrel M fully retracted within the nose piece 14 ofthe puller 12. The end portion 25 of the mandrel M has been movedentirely through the tubular section 30. As a result, the puller 12 andmandrel M are freely movable away from the installed bushing 26, 28.FIG. 8 shows an axial space 48 starting to form between side surface 44of member 40 and end surface 16 of nose piece 14. It further shows thebushing parts 26,28 installed within the opening 18. The installedbushing parts 26, 28, are also shown in FIG. 12, with the puller 12having been moved away from the work member 40.

Following its installation, the inside surface of the tubular section 30might be slightly tapered. In that case the opening in tubular section30 may be reamed to a desired inside diameter and to remove lubricantresidual. The lubricant residual may be present because it is commonpractice to use a lubricant between a mandrel M and a bushing throughwhich the mandrel M is moved.

Movement of the mandrel M through the bushing 25 expands the tubularsection 30 beyond elastic expansion and into plastic expansion. That is,the material is expanded a sufficient amount that it will assume andretain a new diameter.

FIGS. 3, 9 and 13 show another form of two part bushing 50. A firstbushing part 52 has a tubular section 54 and a radial flange section 56at one end of the tubular section 54. As shown by FIGS. 9 and 13, thetubular section 54 has an outside diameter substantially conforming tothe opening 38 in the work member 40. Tubular section 54 has a lengthmeasured from the inside of flange section 56 to its opposite end thatsubstantially corresponds to the length of the opening 38. Bushing part58 has a tubular section 60 and a radial flange section 62 connected toone end of the tubular section 60. Tubular section 60 has an outsidediameter substantially conforming to the inside diameter of tubularsection 54. It has a length substantially conforming to the length ofthe opening in tubular section 54.

The opening 38 is formed and prepared in the manner described above.Primer may be applied to the inside of the opening 38. Sealant may beapplied to the inside surfaces of the flanges 56, 62 of the bushing 50.The bushing 50 is installed in the following manner. The tubular section54 of bushing part 52 is inserted into the opening 38 in the work member40, from the first side of the work member 40. It is then pushed axiallyinwardly until the inner surface of flange section 56 contacts the sidesurface 46 on the work member 40. Then, the tubular section 60 of thebushing part 58 is installed into the opening in bushing section 54,from the second side of the work member. It is moved inwardly until theinner surface of flange section 62 contacts the sidewall 44 of workmember 40. Next, as shown by FIG. 9, the mandrel M and puller 12 areused to radially and circumferentially expand the two tubular sections54, 60. The mandrel M is installed in the manner described above inconnection with FIGS. 6–8 and a lubricant is used between it and thebushing 50. It is then pulled axially into the puller 12 so as to moveits enlarged end portion 24 axially through tubular section 60, as shownin FIG. 9. As it moves, the mandrel head 24 radially andcircumferentially expands both tubular section 60 and tubular section54. This expansion makes a tight interference fit between tubularsection 54 and the sidewall of opening 38 and makes a tight interferencefit of tubular section 60 within tubular section 54. This connectstubular portion 54 to the sidewall of opening 38 and connects tubularportion 60 to tubular portion 54. As can be seen from FIG. 9, movementof the mandrel M through the tubular section 54 applies a drag force onthe bushing part 52 that pulls the flange section 56 into tight contactwith the wall 46 of work member 40. The end surface 16 of nose piece 14is pressed by reaction forces tightly against flange section 62, movingflange section 62 into tight engagement with sidewall 44 of work member40.

FIGS. 4, 10 and 14 disclose a third embodiment of the bushing. Thisbushing 66 has three parts. A tubular first bushing part 68 has anoutside diameter and a length that correspond to the diameter and lengthof opening 38 in work member 40. The second bushing part 70 has atubular section 72 and a radial flange section 74 at one end of thetubular section 72. It has an outside diameter substantially conformingto the inside diameter of bushing part 68. It has a length that isshorter than the opening 38 in work member 40. The third bushing part 76has a tubular section 78 and a radial flange section 80 at one end ofthe tubular section 78. Preferably, bushing parts 70, 76 are alike.Preferably also, the tubular sections 72, 78 are substantially thelength of tubular section 68 and the opening 38 in the work member 40.

Bushing 66 is installed in the following manner. Firstly, bushing part68 is placed in the opening 38 in work member 40. Then, tubular section72 of bushing part 70 is inserted into the bushing part 68 from thefirst side of the work member 40. Bushing part 76 is inserted into thebushing part 68 from the opposite side of the work member. The bushingparts 70, 76 are moved toward each other until radial flange 74 issubstantially against side surface 46 and radial flange 80 issubstantially against side surface 44. Then, the mandrel M and thepuller 12 are used in a manner described above in connection with thefirst two embodiments. Axial movement of the enlarged end portion 24 ofthe mandrel M through the bushing parts 68, 70 radially andcircumferentially expands tubular sections 72, 78, 68. As a result,bushing part 68 is moved into a tight interference fit with the sidewallof opening 38. Tubular sections 72, 78 and bushing part 70, 78 are movedinto a tight interference fit with bushing part 68. Flange section 74 ispulled into tight contact with side surface 46 and flange section 80 ispushed into tight contact with side surface 44. The expansion connectsbushing part 68 to the side surface of opening 38 and connects tubularsections 72, 78 of bushing parts 70, 76 to bushing part 68. Tubularsections 72, 78 may have concentric overlapping portions where theymeet. This is shown by FIG. 17. End portion 72′ is shown toconcentrically surround end portion 78′.

FIGS. 5, 8 and 15 show a fourth embodiment of the bushing. This bushing86 is composed of two bushing parts 88, 90, which are preferablyidentical in construction. Bushing part 88 has a tubular section 92 anda radial flange section 94 that is connected to one end of the tubularsection 92. Bushing part 90 has a tubular section 96 and a radial flangesection 98 that is connected to one end of the tubular section 96. Theoutside diameters of the tubular sections 92, 98 substantially conformto the diameter of the opening 38 in the work member 40. The tubularsections 92, 96 are both shorter than the opening 38 but, preferably,their combined lengths substantially equal the length of the opening 38(FIG. 15). The tubular sections 92, 96 may have concentric end portionsthat form a lap joint where they meet. End part 92′ concentricallysurrounds end part 96′.

The bushing 86 is installed in the following manner. The tubularsections 92, 96 are either installed separately or together into theopening 38 from opposite sides of the work member. The bushing parts 86,90 are moved axially together until flange section 94 substantiallycontacts sidewall 46 and flange section 98 substantially contacts sidesurface 44. Then, the mandrel 20 and the puller 12 are used in themanner described above for radially and circumferentially expanding thetubular sections 92, 98 in the opening 38. As previously described,axial movement of the mandrel 20 through the tubular sections of thebushing acts to pull flange section 94 against sidewall 46 and pushflange section 98 against sidewall 44.

Preferably, the installation of bushings 50, 66, 86 includes radiallyand circumferentially expanding the tubular sections of the bushingparts an amount sufficient to introduce fatigue life enhancingcompressive residual stresses in the work member immediately around theopening 38 in the work member 40.

The various bushing parts that have been described can be made from anysuitable metal that has to date been used for making bushings and fromnew materials that might be developed for use in making bushings, or foruse in making other structures but suitable for use in making bushings.Typical examples are bronze, bronze alloys, brass, brass alloys,aluminum, aluminum-nickel-bronze, copper beryllium, stainless steels andInconel and other high temperature engine alloys, alloys, and carbonsteels, etc. The work member 40 may be a structural wall or it may besome other structural member. It may be made from metal or compositematerials.

The illustrated embodiments are only examples of; the present inventionand, therefore, are non-limitive. It is to be understood that manychanges in the particular structure, materials and features of theinvention may be made without departing from the spirit and scope of theinvention. Therefore, it is my intention that my patent rights not belimited by the particular embodiments illustrated and described herein,but rather determined by the following claims, interpreted according toaccepted doctrines of claim interpretation, including use of thedoctrine of equivalents and reversal of parts.

1. A dual bushing installation comprising: an outer metal bushingcomprising a first body having a first end, an opposite end, and priorto installation, the outer metal bushing includes a single radialflange, the first end and the opposite end connected by acircumferentially seamless outer surface having an outer circumferenceand a circumferentially seamless inner surface having an innercircumference, the circumferentially seamless inner surface adjacent afirst opening that extends through the first body, the single radialflange of the outer bushing proximate the first end of the outer metalbushing; an inner metal bushing comprising a second body having a firstend, a second end, and prior to installation, the inner metal bushingincludes a single radial flange, the first end and the second endconnected by a circumferentially seamless outer surface having an outercircumference and a circumferentially seamless inner surface having aninner circumference, the circumferentially seamless inner surface of theinner bushing adjacent a second opening that extends through the secondbody, the single radial flange of the inner bushing proximate the secondend of the inner metal bushing; wherein the outer circumference of theinner metal bushing substantially conforms with the inner circumferenceof the outer metal bushing such that the inner metal bushing is closelyreceived by the first opening of the outer metal bushing; and whereinthe inner metal bushing is rotationally and translationally fixedrelative to the outer metal bushing because of a sufficient radialdisplacement initiated at the circumferentially seamless inner surfaceof the inner bushing, which provides a substantially equal, outwardlyradial displacement throughout nearly all of a longitudinal length ofthe circumferentially seamless outer surface of the inner metal bushingand nearly all of a longitudinal length of the circumferentiallyseamless inner surface of the outer metal bushing such thatsubstantially uniform stresses are provided along the longitudinallengths of the inner bushing and the outer bushing.
 2. The installationof claim 1 wherein the circumferences are diameters.
 3. The installationof claim 1 wherein the dual-bushing installation kit is received in anopening of a structural work member.
 4. The installation of claim 1wherein the amount of radial displacement achieved at thecircumferentially seamless outer surface of the outer metal bushing isdependent, in part, on the modulus of elasticity and the ultimatestrength of the first and second metal bushings.
 5. The installation ofclaim 1 wherein the first body and the second body are cylindrical andconcentric with respect to one another.
 6. The installation of claim 1,further comprising: a solid metal structural wall having an openingextending between the single radial flange of the outer metal bushingand the single radial flange of the inner metal bushing, the entirecircumferentially seamless outer surface of the outer metal bushingcontacts all of a longitudinal length of a surface of the opening of thestructural wall.
 7. The installation of claim 1 wherein the innercircumference of the inner metal bushing is uniform along all of alongitudinal length of the circumferentially seamless inner surface ofthe inner metal bushing.
 8. The installation of claim 1 wherein theentire circumferentially seamless inner surface of the inner metalbushing defines a passageway having a uniform axial cross-sectionthroughout all of a longitudinal length of the circumferentiallyseamless inner surface of the inner metal bushing.
 9. A dual bushinginstallation kit comprising: a first metal bushing comprising a firstbody having first and second ends, the first and second ends connectedby a first outer surface having a first outer circumference and a firstinner surface having a first inner circumference, the first innersurface surrounding a first opening that extends through the first body;a second metal bushing defined by a second body having first and secondends, the first and second ends connected by a second outer surfacehaving a second outer circumference and a second inner surface having asecond inner circumference, the second inner surface surrounding asecond opening that extends through the second body; wherein the secondouter circumference dimensioned to be substantially conforming with thefirst inner circumference such that the second bushing is closelyreceivable by the first opening of the first bushing; wherein sufficientradial displacement initiated at the second inner surface of the secondbody results in substantially equal displacement of both the secondouter circumference and the first inner circumference in an outwardlyradial direction; and wherein the first body and the second body areelliptical, the first inner surface of the first bushing having a firstelliptical profile that substantially conforms to a second ellipticalprofile defined by the second outer surface of the second bushing.
 10. Aradially, cold-expandable, dual bushing assembly comprising: an outermetal bushing comprising a first body having a first end, an oppositeend, and prior to installation, the outer metal bushing includes onlyone radial flange, the first end and the opposite end connected by afirst circumferentially seamless outer surface and a firstcircumferentially seamless inner surface, the first circumferentiallyseamless inner surface adjacent a first opening that extends through thefirst body, the only one radial flange of the outer bushing proximatethe first end of the outer metal bushing; an inner metal bushingcomprising a second body having a first end, a second end, and prior toinstallation, the inner metal bushing includes only one radial flange,the first end and the second end connected by a second circumferentiallyseamless outer surface and a second circumferentially seamless innersurface, the second circumferentially seamless inner surface adjacent anopening that extends through the second body, the only one radial flangeof the inner bushing proximate the second end of the inner metalbushing; wherein the second circumferentially seamless outer surface ofthe inner metal bushing is received in and substantially conforms withthe first circumferentially seamless inner surface of the outer metalbushing; wherein the inner and outer bushings are radially expanded by alike amount because of the second circumferentially seamless innersurface of the second body being radially displaced; and whereincompressive stresses are developed in the inner metal bushing, the outermetal bushing, and in an area of a work member that receives the outermetal bushing because of the second circumferentially seamless innersurface of the second body being radially displaced, the compressivestresses being sufficient to increase the fatigue life of the workmember.
 11. The assembly of claim 10 wherein an amount of radialdisplacement of the second circumferentially seamless outer surface ofthe second metal bushing depends, in part, on the modulus of elasticityand the ultimate strength of the first and second metal bushings. 12.The assembly of claim 10 wherein the first body and the second body arecylindrical and concentric with respect to one another.
 13. The assemblyof claim 10 wherein the compressive stresses are substantial uniformalong nearly all of a longitudinal length of the inner bushing andnearly all of a longitudinal length of the outer bushing.
 14. Aradially, cold-expandable, dual bushing assembly comprising: a first,non-expanded, metal bushing defined by a first body having first andsecond ends, the first and second ends connected by a first outersurface and a first inner surface, the first inner surface surrounding afirst opening that extends through the first body; a second,non-expanded, metal bushing defined by a second body having first andsecond ends, the first and second ends connected by a second outersurface and a second inner surface, the second inner surface surroundingan opening that extends through the second body; wherein the bushings intheir non-expanded state provide for the second outer circumferencedimensioned to be substantially conforming with the first innercircumference such that the second bushing is closely insertable intothe first opening of the first bushing; wherein the non-expanded bushingassembly is capable of substantially equal displacement of both thesecond outer circumference and the first inner circumference in anoutwardly radial direction when a radial displacement is initiated atthe second inner surface of the second body; wherein compressivestresses are developed in the first bushing and compressive stresses arefurther developed in an area of a work member that is contiguous withand substantially surrounding the first bushing when the radialdisplacement is initiated at the second inner surface of the secondbody, the compressive stresses being sufficient to increase the fatiguelife of the work member; and wherein the first body and the second bodyare elliptical, the first inner surface of the first bushing having afirst elliptical profile that substantially conforms to a secondelliptical profile defined by the second outer surface of the secondbushing.